Question: Simplify the following expression: $p = \dfrac{t^2 + 19t + 90}{t + 9} $
Explanation: First factor the polynomial in the numerator. $ t^2 + 19t + 90 = (t + 9)(t + 10) $ So we can rewrite the expression as: $p = \dfrac{(t + 9)(t + 10)}{t + 9} $ We can divide the numerator and denominator by $(t + 9)$ on condition that $t \neq -9$ Therefore $p = t + 10; t \neq -9$